The following approaches will be explored or continued over the next year: 1. Limit dilution studies of influenza-immune cytotoxic T cell frequency and specificity for both primed and naive mouse lymphocyte populations. This approach will also be applied to the analysis of high and low responder situations. 2. Production of highly potent influenza-immune T cell populations in vitro, and the use of these lymphocytes for immunization of rats in attempts to produce monoclonal antibodies specific for influenza-specific T cell subjects. 3. Continuing investigation of the recirculation and localization characteristics of influenza-immune TDL, particularly with respect to sites of virus growth in the lung and central nervous system. 4. Further analysis of the influence of monoclonal antibodies administered intravenously on the pathogenesis of intracerebrally injected A/WSN influenza virus, specifically with regard to effects on virus growth characteristics and modulation of the inflammatory process. 5. Characteristics of the blocking of influenza-specific T cell effector function and stimulation, both in vitro and in vivo, using defined monoclonal antibody populations produced in the laboratory of Dr. W. Gerhard. 6. A search, using immunofluorescent and cytotoxicity protocols, for idiotype-specific T cell subsets with antibodies produced against hybridoma products specific for the influenza A viruses.